Ubuntu 17.04 and later

VirtualBox sets up the vboxnet0 virtual interface routing using the legacy ifconfig and route
commands, instead of the modern ip command. For networking to work properly, you need to run
apt install net-tools.

Linux (Fedora)

Add RPMFusion repositories. See RpmFusion. Repository is
needed for Virtualbox.

Linux (General)

If you get errors related to creating host-only network adapters during vagrant up, run sudo vboxreload.
It seems that sometimes virtualbox kernel modules are not working correctly after the machine wakes up from sleep.